Part B Directions: In the following
article, some sentences have been removed. For Questions 41-45, choose the most
suitable one from the list A-G to fit into each of the numbered blanks. There
are two extra choices, which do not fit in any of the blanks.
Long before man lived on the Earth, there were fishes,
reptiles, birds, insects, and some mammals. Although some of these animals were
ancestors of kinds living today, others are now extinct, that is, they have no
descendants alive now. Nevertheless, we know a great deal about many of them
because their bones and shells have been preserved in the rocks as fossils.
41.______That kind of rock in which the remains are found
tells us much about the nature of the original land, often of the plants that
grew on it, and even of its climate. When an animal dies,
the body, its bones, or shell, may often be carried away by streams into lakes
or the sea and there get covered up by mud. If the animal lived in the sea its
body would probably sink and be covered with mud. More and more mud would fall
upon it until the bones or shell become embedded and preserved. 42．______Thus it
follows that there must be many kinds of mammals, birds, and insects of which we
know nothing, 43．______Later forms are more complex, and
among these are the sea-lilies, relations of the star-fishes, which had long
arms and were attached by a long stalk to the sea bed, or to rocks. There were
also crab-like creatures, whose bodies were covered with a horny substance, The
body segments each had two pairs of legs, one pair for walking on the sandy
bottom, the other for swimming. The head was a kind of shield with a pair of
compound eyes, often with thousands of lenses. They were usually an inch or two
long but some were 2 feet. The shellfish have a long
history in the rock and many different kinds are known. Of these, the ammonites
are very interesting and important. They have a shell composed of many chambers,
each representing a temporary home of the animal. As the young grew larger it
grew a new chamber and sealed off the previous one. Thousands of these can be
seen in the rocks on the Dorset Coast. The first animals
with true backbones were fishes, first known in the rocks of 375 million years
ago. About 300 million years ago the amphibians, the animals able to live both
on land and in water, appeared. They were giant, sometimes 8 feet long, and many
of them lived in the swampy pools in which our coal seam, or layer, formed.
44．______About 75 million years ago the Age of Reptiles was over and most of the
groups died out. The mammals quickly developed, and we can trace the evolution
of many familiar animals such as the elephant and horse. 45．______
[A] The best index fossils tend to be marine creatures.
These animals evolved rapidly and spread over large areas of the world.
[B] The amphibians gave rise to the reptiles and for
nearly 150 million years these were the principal forms of life on land, in the
sea, and in the air. [C] Many of the later mammals,
though now extinct, were known to primitive man and were featured by him in cave
paintings and on bone carvings. [D] Nearly all of the
fossils that we know were preserved in rocks formed by water action, and most of
these are of animals that lived in or near water. [E] The
earliest animals whose remains have been found were all very simple kinds and
lived in the sea. [F] Many factors can influence how
fossils are preserved in rocks. Remains of an organism may be replaced by
minerals, dissolved by an acidic solution to leave only their impression, or
simply reduced to a more stable form. [G] From them we
can tell their size and shape, how they walked, the kind of food they ate. Very
occasionally the rocks show impression of skin, so that, apart from color, we
can build up a reasonably accurate picture of an animal that died millions of
years ago.